Summary. Deduplicate lines across one or more input files while preserving structure: every unique line is kept; every duplicate line is kept only at its first occurrence; and for each unique line we keep up to N lines of context (the lines immediately before it). Blank or whitespace-only lines are never deduplicated. Output order is the same as input order. Useful for compressing multi-page HTML→markdown where repeated headers/nav would be removed by block dedup, but we still want one copy of shared content and local context around unique content.
node compress.js [options] file1 [file2 ...]
